staging: comedi: das16: use cfc_bytes_per_scan()

Use the comedi_fc helper to get the number of bytes per scan.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: NIan Abbott <abbotti@mev.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/das16.c

@@ -762,8 +762,7 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s)
 		return -1;
 	}
 
-	devpriv->adc_byte_count =
-	    cmd->stop_arg * cmd->chanlist_len * sizeof(uint16_t);
+	devpriv->adc_byte_count = cmd->stop_arg * cfc_bytes_per_scan(s);
 
 	if (devpriv->can_burst)
 		outb(DAS1600_CONV_DISABLE, dev->iobase + DAS1600_CONV_REG);